Forget Eliot Spitzer and Condit, Craig, Foley, Frank, Hart, McGreevey and Vitter. One fine sex scandal hasn't yet been mentioned, so I'll do it.
About 2,500 years ago, King Candaules of Lydia arranged for a courtier to peep into his bedchamber and spy on his wife, the queen, as she undressed, according to Herodotus. Unbeknownst to Candaules, the queen spotted Gyges peering at her. The queen later summoned Gyges and offered him a choice: "Slay Candaules, and thereby become my lord, and obtain the Lydian throne, or die this moment in his room."
Herodotus wrote: "All was then prepared for the attack, and when night fell, Gyges, seeing that he had no retreat or escape, but must absolutely either slay Candaules, or himself be slain, followed his mistress into the sleeping-room. She placed a dagger in his hand and hid him carefully behind the self-same door. Then Gyges, when the king was fallen asleep, entered privily into the chamber and struck him dead."
Juicy stuff! "Client Nine" and "things you might not think were safe" are tame by comparison.
Read the rest of the story from The Histories on the website of the MIT classics department. Search the document for 'Candaules.'
I've always felt a kinship to Herodotus. The Helicarnassian writes like a journalist, citing sources:
Thus did Io pass into Egypt, according to the Persian story, which differs widely from the Phoenician: and thus commenced, according to their authors, the series of outrages.
The man also knows how to win over an audience. The tale of Candaules is right at the start of The Histories. Even back then, in 400 BCE, sex sold.
